A. 
For the purposes of this chapter, certain terms and words used herein shall be interpreted as follows:
(1) 
Words used in the present tense include the future tense; the singular number includes the plural, and the plural number includes the singular; words of masculine gender include feminine gender; and words of feminine gender include masculine gender.
(2) 
The word "includes" or "including" shall not limit the term to the specific example but is intended to extend its meaning to all other instances of like kind and character.
(3) 
The word "person" includes an individual, firm, association, organization, partnership, trust, company, corporation, or any other similar entity.
(4) 
The words "shall" and "must" are mandatory; the words "may" and "should" are permissive.
(5) 
The words "used" or "occupied" include the words "intended," "designed," "maintained," or "arranged to be used," "occupied" or "maintained."
B. 
As used in this chapter, the following terms shall have the meanings indicated:
ACCELERATED EROSION
The removal of the surface of the land through the combined action of man's activity and the natural processes of a rate greater than would occur because of the natural process alone.
AGRICULTURAL ACTIVITIES
Activities associated with agriculture such as agricultural cultivation, agricultural operation, and animal heavy use areas. This includes the work of producing crops including tillage, land clearing, plowing, disking, harrowing, planting, harvesting crops or pasturing and raising livestock and installation of conservation measures. Construction of new buildings or impervious area is not considered an agricultural activity.
ALTERATION
As applied to land, a change in topography as a result of the moving of soil and rock from one location or position to another; also the changing of surface conditions by causing the surface to be more or less impervious; land disturbance.
APPLICANT
A landowner or developer who has filed an application for approval to engage in any regulated activities as defined in § 129-4 of this chapter.
AS-BUILT DRAWINGS (AS-BUILT PLAN)
Drawings that are maintained during construction of the project and which document the actual locations of the site improvements. As-built plan must be prepared by a professional land surveyor, landscape architect, or professional engineer licensed in the Commonwealth of Pennsylvania.
BANKFULL
The channel at the top of bank or point where water begins to overflow onto a floodplain.
BASE FLOW
The portion of stream flow that is sustained by groundwater discharge.
BIORETENTION
A stormwater retention area which utilizes woody and herbaceous plants and soils to remove pollutants before infiltration occurs.
BMP (BEST MANAGEMENT PRACTICE)
Activities, facilities, designs, measures, or procedures used to manage stormwater impacts from regulated activities, to meet state water quality requirements, to promote groundwater recharge, and to otherwise meet the purposes of this chapter. Stormwater BMPs are commonly grouped into one of two broad categories or measures: structural or nonstructural. In this chapter, nonstructural BMPs or measures refer to operational and/or behavior-related practices that attempt to minimize the contact of pollutants with stormwater runoff whereas structural BMPs or measures are those that consist of a physical device or practice that is installed to capture and treat stormwater runoff. Structural BMPs include, but are not limited to, a wide variety of practices and devices, from large-scale retention ponds and constructed wetlands, to small-scale underground treatment systems, infiltration facilities, filter strips, low-impact design, bioretention, wet ponds, permeable paving, grassed swales, riparian or forested buffers, sand filters, detention basins, and manufactured devices. Structural stormwater BMPs are permanent appurtenances to the project site.
BMP MANUAL
Pennsylvania Stormwater Best Management Practices Manual, December 2006, as amended.
CHANNEL
An open drainage feature through which stormwater flows. Channels include but shall not be limited to natural and man-made watercourses, swales, streams, ditches, canals, and pipes that convey continuously or periodically flowing water.
CHANNEL EROSION
The widening, deepening, and headward cutting of channels and waterways due to erosion caused by moderate to large floods.
CONSERVATION DISTRICT
Montgomery County Conservation District.
COUNTY
Montgomery County.
CULVERT
A pipe, conduit, or similar structure including appurtenant works which conveys surface water under or through an embankment or fill.
CURVE NUMBER (CN)
Value used in the Soil Cover Complex Method. It is a measure of the percentage of precipitation which is expected to run off from the watershed and is a function of the soil, vegetative cover, and tillage method.
DAM
An artificial barrier, together with its appurtenant works, constructed for the purpose of impounding or storing water or another fluid or semifluid, or a refuse bank, fill or structure for highway, railroad, or other purposes which does or may impound water or another fluid or semifluid.
DEPARTMENT
The Pennsylvania Department of Environmental Protection.
DESIGN PROFESSIONAL (QUALIFIED)
A Pennsylvania registered professional engineer, registered landscape architect, or a registered professional land surveyor trained to develop stormwater management site plans on simplified stormwater management site plans.
DESIGN STORM
The magnitude and temporal distribution of precipitation from a storm event measured in probability of occurrence (e.g., fifty-year storm) and duration (e.g., 24 hours), used in the design and evaluation of stormwater management systems.
DESIGNEE
The agent of Worcester Township, Montgomery County, Montgomery County Conservation District and/or governing body involved with the administration, review, or enforcement of any provisions of this chapter by contract or memorandum of understanding.
DETENTION BASIN
An impoundment structure designed to manage stormwater runoff by temporarily storing the runoff and releasing it at a predetermined rate. Detention basins are designed to drain completely soon after a rainfall event.
DETENTION VOLUME
The volume of runoff that is captured and released into the waters of the commonwealth at a controlled rate.
DETENTION/RETENTION BASIN WATERSHED
All land area whose surface runoff is captured by a detention and/or retention basin.
DEVELOPER
A person, partnership, association, corporation, or other entity, or any responsible person therein or agent thereof, that undertakes any regulated activity of this chapter.
DEVELOPMENT
Any man-made change to improved or unimproved real estate including, but not limited to, the construction or placement of buildings or other structures, mobile homes, streets and other paving, utilities, mining, dredging, filling, grading, excavation, or drilling operations, and the subdivision of land.
DEVELOPMENT PLAN
The provisions for development including a planned residential development, a plat of subdivision, all covenants relating to use, location and bulk of buildings and other structures, intensity of use or density of development, streets, ways and parking facilities, common open space and public facilities. The phrase "development plan" when used in this chapter shall mean the written and graphic materials referred to in this definition.
DEVELOPMENT SITE
The specific tract of land for which a regulated activity is proposed.
DIFFUSED DRAINAGE DISCHARGE
Drainage discharge not confined to a single point location or channel, such as sheet flow or shallow concentrated flow.
DISCHARGE
(1) 
(Verb) To release water from a project, site, aquifer, drainage basin or other point of interest;
(2) 
(Noun) The rate and volume of flow of water such as in a stream, generally expressed in cubic feet per second (CFS).
DISCONNECTED IMPERVIOUS AREA (DIA)
An impervious surface that is disconnected from any stormwater drainage or conveyance system and is redirected or directed to a pervious area, which allows for infiltration, filtration, and increased time of concentration.
DISTURBED AREA
Unstabilized land area where an earth disturbance activity is occurring or has occurred.
DOWNSLOPE PROPERTY LINE
That portion of the property line of the lot, tract, or parcels of land being developed located such that all overland or pipe flow from the site would be directed toward it.
DRAINAGE EASEMENT
A right granted by a landowner to a grantee, allowing the use of private land for stormwater management purposes.
EARTH DISTURBANCE
A construction or other human activity which disturbs the surface of land, including, but not limited to, clearing and grubbing, grading, excavations, embankments, land development, agricultural plowing or tilling, timber harvesting activities, road maintenance activities, mineral extraction, and the moving, depositing, stockpiling or storing of soil, rock or earth materials.
EMERGENCY SPILLWAY
A conveyance area that is used to pass peak discharge greater than the maximum design storm controlled by the stormwater facility.
ENCROACHMENT
A structure or activity that changes, expands or diminishes the course, current or cross section of a watercourse, floodway or body of water.
ENGINEER
A licensed professional civil engineer registered by the Commonwealth of Pennsylvania.
EROSION
The movement of soil particles by the action of water, wind, ice, or other natural forces.
EROSION AND SEDIMENTATION CONTROL PLAN
A plan which is designed to minimize accelerated erosion and sedimentation.
EXCEPTIONAL VALUE WATERS
Surface waters of high quality which satisfy Pennsylvania Code Title 25 Environmental Protection, Chapter 93, Water Quality Standards, § 93.4b(b) (relating to antidegredation).
EXISTING CONDITION
The initial condition of a project site prior to the proposed construction. Farm field, disturbed earth, or undeveloped cover conditions of a site or portions of a site used for modeling purposes, shall be considered "meadow" unless the natural groundcover generates lower curve numbers or Rational "C" value, such as forested land. Existing man-made impervious surfaces shall be considered as "meadow" when developing "cover complex" calculations.
EXISTING RECHARGE AREA
Undisturbed surface area or depression where stormwater collects and a portion of which infiltrates and replenishes the groundwater.
EXISTING RESOURCES AND SITE ANALYSIS MAP
A base map which identifies fundamental environmental site information including floodplains, wetlands, topography, vegetative site features, natural areas, prime agricultural land and areas supportive of endangered species.
FLOOD
A general but temporary condition of partial or complete inundation of normally dry land areas from the overflow of streams, rivers, and other waters of this commonwealth.
FLOODPLAIN
Those areas of Worcester Township which are subject to the 100-year flood, as identified in the Flood Insurance Study (FIS) dated December 19, 1996, and the accompanying maps prepared for the Township by the Federal Emergency Management Agency (FEMA), or most recent revision thereof; and also those areas along streams, ponds, or lakes not identified within the Flood Insurance Study which are inundated by the 100-year reoccurrence internal flood.
FLOODWAY
The channel of the watercourse and those portions of the adjoining floodplains that are reasonably required to carry and discharge the 100-year frequency flood. Unless otherwise specified, the boundary of the floodway is as indicated on maps and flood insurance studies provided by FEMA. In an area where no FEMA maps or studies have defined the boundary of the 100-year frequency floodway, it is assumed, absent evidence to the contrary, that the floodway extends from the stream to 50 feet from the top of the bank of the stream.
FOREST MANAGEMENT/TIMBER OPERATIONS
Planning and activities necessary for the management of forestland. These include timber inventory and preparation of forest management plans, silvicultural treatment, cutting budgets, logging road design and construction, timber harvesting, site preparation, and reforestation.
FREEBOARD
A vertical distance between the elevation of the design high-water and the top of a dam, levee, tank, basin, or diversion ridge. The space is required as a safety margin in a pond or basin.
GRADE
(1) 
(Noun) A slope usually of a street, other public way, land area, drainage facility or pipe specified in percent;
(2) 
(Verb) To finish the surface of a road bed, top of embankment or bottom of excavation.
GROUNDWATER
Water beneath the earth's surface that supplies wells and springs, and is often between saturated soil and rock.
GROUNDWATER RECHARGE
Replenishment of natural underground water supplies.
HEC-HMS
The United States Army Corps of Engineers, Hydrologic Engineering Center (HEC) — Hydrologic Modeling System (HMS).
HIGH-QUALITY WATERS
Surface waters having quality which exceeds levels necessary to support propagation of fish, shellfish, and wildlife and recreation in and on the water by satisfying Pennsylvania Code Title 25 Environmental Protection, Chapter 93, Water Quality Standards, § 93.4b(a).
HOT SPOT
An area where land use or activity generates highly contaminated runoff, with concentrations of pollutants in excess of those typically found in stormwater. Typical pollutant loadings in stormwater may be found in Chapter 8, Section 6, of the Pennsylvania Stormwater Best Management Practices Manual, Pennsylvania Department of Environmental Protection (PADEP) No. 363-0300-002 (2006).
HYDRIC SOIL
A soil that is saturated, flooded, or ponded long enough during the growing season to develop anaerobic condition in the upper part.
HYDROLOGIC REGIME (NATURAL)
The hydrologic cycle or balance that sustains quality and quantity of stormwater, baseflow, storage, and groundwater supplies under the natural conditions.
HYDROLOGIC SOIL GROUP
A classification of soils by the Natural Resources Conservation Service, formerly the Soil Conservation Service, into four runoff potential groups. The groups range from A soils, which are very permeable and produce little runoff, to D soils, which are not very permeable and produce much more runoff.
IMPERVIOUS SURFACE (IMPERVIOUS AREA)
A surface that prevents the infiltration of water into the ground. Impervious surface area shall include, but not be limited to, buildings, parking areas, driveways, roads, and sidewalks. Any areas containing concrete, asphalt, compacted stone, compacted soils, or other equivalent surfaces shall be considered impervious. Decks that do not prevent infiltration shall not be considered as impervious surface. In addition, other areas determined by the Township Engineer to be impervious within the meaning of this definition shall be classified as impervious surface. Any area initially designated to be gravel or crushed stone shall be assumed to be impervious. Pervious paving, when designed above a stormwater storage/infiltration system may be considered as pervious surface as approved by the Township Engineer.
IMPOUNDMENT
A retention or detention basin designed to retain stormwater runoff and release it at a controlled rate.
INFILTRATION
Movement of surface water into the soil, where it is absorbed by plant roots, evaporated into the atmosphere or percolated downward to recharge groundwater.
INFILTRATION STRUCTURE
A structure designed to direct runoff into the ground (e.g., french drains, seepage pits, seepage trench, biofiltration swale).
INLET
A surface connection to a closed drain. A structure at the diversion end of a conduit. The upstream end of any structure through which water may flow.
INVERT
The inside bottom of a culvert or other conduit.
LAND DEVELOPMENT
Any of the following activities:
(1) 
The improvement of one or two or more contiguous lots, tracts or parcels of land for any purpose involving:
(a) 
A group of two or more residential or nonresidential buildings, whether purposed initially or cumulatively, or a single nonresidential building on a lot or lots regardless of the number of occupants or tenure; or
(b) 
The division or allocation of land or space, whether initially or cumulatively, between or among two or more existing or prospective occupants by means of, or for the purpose of, streets, common areas, leaseholds, condominiums, building groups or other features.
(2) 
A subdivision of land.
(3) 
Land development does not include development which involves:
(a) 
The conversion of an existing single-family detached dwelling or single-family semidetached dwelling into not more than three residential units, unless such units are intended to be a condominium;
(b) 
The addition of a residential accessory building, including farm building, on a lot or lots subordinate to an existing principal building; or
(c) 
The addition or conversion of buildings or rides within the confines of an enterprise which would be considered an amusement park. For the purposes of this subsection, an "amusement park" is defined as a tract or area used principally as a location for permanent amusement structures or rides. This exclusion shall not apply to newly acquired acreage by an amusement park until initial plans for the expanded area have been approved by the proper authorities.
LAND/EARTH DISTURBANCE
Any activity involving grading, tilling, digging, or filling of ground or stripping of vegetation or any other activity that causes an alteration to the natural condition of the land.
LIMITING ZONE
A soil horizon or condition in the soil profile or underlying strata which includes one of the following:
(1) 
A seasonal high water table, whether perched or regional, determined by direct observation of the water table or indicated by soil mottling.
(2) 
A rock with open joints, fracture or solution channels, or masses of loose rock fragments, including gravel, with insufficient fine soil to fill the voids between the fragments.
(3) 
A rock formation, other stratum or soil condition which is so slowly permeable that is effectively limits downward passage of effluent.
LOW-IMPACT DEVELOPMENT (LID) PRACTICES
Practices that will minimize proposed conditions runoff rates and volumes, which will minimize the need for artificial conveyance and storage facilities.
MANNING EQUATION (MANNING FORMULA)
A method for calculation of velocity of flow (e.g., feet per second) and flow rate (e.g., cubic feet per second) in open channels based upon channel shape, roughness, depth of flow and slope. "Open channels" may include closed conduits so long as the flow is not under pressure.
MS4 - MUNICIPAL SEPARATE STORM SEWER SYSTEM
Pursuant to 40 CFR 122.26(b)(8), municipal separate storm sewer system is a conveyance of system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains):
(1) 
Owned or operated by a state, city, town, township, county, parish, district, association, or other public body (created to or pursuant to state law) including special districts under state law such as a sewer district, flood control district or drainage district, or similar entity, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under Section 208 of the Clean Water Act that discharges into waters of the United States;
(2) 
Designed or used for collecting or conveying stormwater;
(3) 
Which is not a combined sewer; and
(4) 
Which is not part of a publicly owned treatment works as defined at 40 CFR 122.2.
NONPOINT SOURCE POLLUTION
Pollution that enters a watery body from diffuse origins in the watershed and does not result from discernible, confined, or discrete conveyances.
NONSTORMWATER DISCHARGE
Water flowing in stormwater collection facilities, such as pipes or swales, which is not the result of a rainfall event or snowmelt.
NPDES
National Pollution Discharge Elimination System, the federal government's system for issuance of permits under the Clean Water Act,[1] which is delegated to PADEP in Pennsylvania.
NRCS
Natural Resource Conservation Service (previously SCS).
OPEN CHANNEL
A drainage element in which stormwater flows with an open surface. Open channels include, but shall not be limited to, natural and man-made drainageways, swales, streams, ditches, canals, and pipes flowing partly full.
OUTFALL
"Point source" as described in 40 CFR 122.2 at the point where Worcester Township's storm sewer system discharges to surface waters of the commonwealth.
OUTLET
Points of water disposal from a stream, river, lake, tidewater or artificial drain.
PADEP
The Pennsylvania Department of Environmental Protection.
PARENT TRACT
The parcel of land from which a land development or subdivision originates as of the date of adoption of this chapter.
PEAK DISCHARGE
The maximum rate of stormwater runoff from a specific storm event.
PIPE
A culvert, closed conduit, or similar structure (including appurtenances) that conveys stormwater.
PLANNING COMMISSION
The Planning Commission of Worcester Township.
PMF (PROBABLE MAXIMUM FLOOD)
The flood that may be expected from the most severe combination of critical meteorological and hydrologic conditions that are reasonably possible in any area. The PMF is derived from the probable maximum precipitation (PMP) as determined on the basis of data obtained from the National Oceanographic and Atmospheric Administration (NOAA).
POINT SOURCE
Any discernible, confined and discrete conveyance, including, but not limited to, any pipe, ditch, channel, tunnel, or conduit from which stormwater is or may be discharged, as defined in state regulations at 25 Pa. Code § 92.1.[2]
POSTDEVELOPMENT
Period after construction during which disturbed areas are stabilized, stormwater controls are in place and functioning, and all improvements in the approved stormwater management plan are completed.
PRETREATMENT
Techniques employed in stormwater BMPs to provide storage or filtering to help trap coarse materials and other pollutants before they enter the system.
RATIONAL METHOD
A rainfall-runoff relation used to estimate peak flow.
RECHARGE AREA
Undisturbed surface area or depression where stormwater collects, and a portion of which infiltrates and replenishes the underground and groundwater.
RECHARGE VOLUME
A calculated volume of stormwater runoff from impervious areas which is required to be infiltrated at a site and may be achieved through use of structural or nonstructural BMPs.
REGULATED ACTIVITIES
Any activity to which this chapter is applicable pursuant to § 129-4.
REGULATED EARTH DISTURBANCE ACTIVITY
Activity involving earth disturbance subject to regulation under 25 Pa. Code Chapter 92,[3] 25 Pa. Code Chapter 102 or the Clean Streams Law.[4]
RELEASE RATE
The percentage of predevelopment peak rate of runoff from a site or subarea to which the postdevelopment peak rate of runoff must be reduced to protect downstream areas.
RETENTION BASIN
A basin designed to retain stormwater runoff so that a permanent pool is established.
RETENTION VOLUME/REMOVED RUNOFF
The volume of runoff that is captured and not released directly into the surface waters of the commonwealth during or after a storm event.
RETURN PERIOD
The average interval, in years, within which a storm event of a given magnitude can be expected to recur. For example, the 25-year return period rainfall would be expected to recur on the average once every 25 years.
RIPARIAN CORRIDOR
A vegetated ecosystem along a water body that serves to buffer the water body from the effects of runoff by providing water quality filtering, bank stability, recharge, rate attenuation and volume reduction, and shading of the water body by vegetation. Riparian corridors also provide habitat and may include streambanks, wetlands, floodplains, and transitional areas.
RISER
A vertical pipe extending from the bottom of a pond that is used to control the discharge rate from the pond for a specified design storm.
ROAD MAINTENANCE
Earth disturbance activities within the existing road cross section, such as grading and repairing existing unpaved road surfaces, cutting road banks, cleaning or clearing drainage ditches and other similar activities.
ROOF DRAIN
A drainage conduit or pipe that collects water runoff from a roof and leads it away from a structure.
RUNOFF
Any part of precipitation that flows over the land surface.
SEDIMENT BASIN
A barrier, dam, or retention or detention basin located and designed to retain rock, sand, gravel, silt, or other material transported by water.
SEDIMENT POLLUTION
The placement, discharge or any other introduction of sediment into the waters of the commonwealth occurring from the failure to design, construct, implement or maintain control measures and control facilities in accordance with the requirements of this chapter.
SEDIMENTATION
The process by which mineral or organic matter is accumulated or deposited by the movement of water.
SEEPAGE PIT/SEEPAGE TRENCH
An area of excavated earth filled with loose stone or similar coarse material, into which surface water is directed for infiltration into the underground water (Refer to Pennsylvania BMP Manual, December 2006, Chapter 6, Section 4).
SEPARATE STORM SEWER SYSTEM
A system of pipes, open channels, streets, and other conveyances intended to carry stormwater runoff.
SHALLOW CONCENTRATED FLOW
Stormwater runoff flowing in shallow, defined ruts prior to entering a defined channel or waterway.
SHEET FLOW
Runoff that flows over the ground surface as a thin, even layer, not concentrated in a channel.
SOIL GROUP, HYDROLOGIC
A classification of soils by the NRCS into four runoff potential groups. The groups range from A soils, which are very permeable and produce little runoff, to D soils, which are not very permeable and produce much more runoff.
SOIL-COVER COMPLEX METHOD
A method of runoff computation developed by the NRCS that is based on relating soil type and land use/cover to a runoff parameter called a Curve Number (CN).
SPECIAL PROTECTION WATERSHEDS
Watersheds of streams that have been designated in Pennsylvania Code Title 25, Environmental Protection, Chapter 93, Water Quality Standards, as being exceptional-value (EV) or high-quality (HQ) waters.
SPILLWAY
A depression in the embankment of a pond or basin which is used to pass peak discharge greater than the maximum design storm controlled by the pond.
STORAGE INDICATION METHOD
A reservoir routing procedure based on solution of the continuity equation (inflow minus outflow equals the change in storage) with outflow defined as a function of storage volume and depth.
STORM FREQUENCY
The number of times that a given storm event occurs or is exceeded on the average in a stated period of years. Refer to "return period."
STORM SEWER
A system of pipes and/or open channels that convey intercepted runoff and stormwater from other sources, but excludes domestic sewage and industrial wastes.
STORMWATER
The surface runoff generated by precipitation reaching the ground surface.
STORMWATER CONVEYANCE FACILITY (RUNOFF CONVEYANCE FACILITY)
A stormwater management facility designed to transmit stormwater runoff which shall include streams, channels, swales, pipes, conduits, culverts, storm sewers, etc.
STORMWATER MANAGEMENT (SWM)
The control of surface runoff generated by precipitation reaching the ground surface.
STORMWATER MANAGEMENT FACILITY
Any structure, natural or man-made, that, due to its condition, design, or construction, conveys, stores, or otherwise affects stormwater runoff. Typical stormwater management facilities include, but are not limited to, detention and retention basins, open channels, storm sewers, pipes, and infiltration structures.
STORMWATER MANAGEMENT PERMIT
A permit issued by the Township after the stormwater management site plan (SMSP) or the simplified stormwater management site plan (SSMSP) has been approved. Said permit is issued prior to or with the final Township approval.
STORMWATER MANAGEMENT PLAN
The plan for managing stormwater runoff within the Township adopted as required by the Act of October 4, 1978, P.L. 864 (Act 167).[5]
STORMWATER MANAGEMENT SITE PLAN (SMSP)
The stormwater management site plan prepared by the applicant indicating how stormwater runoff will be managed at the particular site of interest according to this chapter.
STORMWATER MANAGEMENT SITE PLAN, SIMPLIFIED (SSMSP)
The simplified stormwater management site plan prepared by the applicant indicating how stormwater runoff will be managed at the particular site of interest according to this chapter.
STREAM
Rivers, creeks, springs, and other perennial or intermittent watercourses containing water at least on a seasonal basis during an average water year. The term "stream" shall include all intermittent streams and all perennial streams.
(1) 
SPRING or SEEPThe point where groundwater discharges to become surface water.
(2) 
STREAM, EPHEMERALA reach of stream that flows only during and for short periods following precipitation, and flows in low areas that may or may not be a well-defined channel. Ephemeral streambeds are located above the water table year round. Groundwater is not a source of water for the stream. Some commonly used names for ephemeral streams include: stormwater channel, drain, swale, gully, dry stream channel, hollow, or saddle.
(3) 
STREAM, HEADWATERThe beginning reach of a stream, which collects water from springs and seeps and provides a hydrologic connection to a perennial stream. These channels may be ill defined and may move from year to year depending upon groundwater input, snowmelt, and runoff, but are typified by hydric soils and hydric vegetation.
(4) 
STREAM, INTERMITTENTA reach of stream that flows only during wet periods of the year and flows in a continuous well-defined channel. During dry periods, when the water table is depressed by seasonal aridity or drought, intermittent streams may go down to a trickle of water and appear dry, when in fact there is water flowing within the stream bottom or "substrate."
(5) 
STREAM, PERENNIAL or WATERCOURSE, PERENNIALA body of water in a channel that flows throughout a majority of the year in a defined channel and is capable, in the absence of pollution, drought, or man-made stream disturbances, of supporting a benthic macroinvertebrate community that is composed of two or more recognizable taxonomic groups of organisms, large enough to be seen by the unaided eye and can be retained by a U.S. Standard No. 30 sieve (28 meshs per inch, 0.595mm openings) and live at least part of their life cycles within or upon available substrates in a body of water or water transport system. A perennial stream can have Q7-10 flow of zero. For the purposes of this document, a perennial stream includes lakes and ponds.
STREAM BANK EROSION
The widening, deepening or headward cutting of channels and waterways caused by stormwater runoff or bankfull flows.
STREAM BUFFER
The land area adjacent to each side of a stream, essential to maintaining water quality.
STREAM ENCLOSURE
A bridge, culvert, or other structure, as defined by 25 Pa. Code Chapter 105, which encloses a regulated water of the Commonwealth of Pennsylvania.
SUBAREA (SUBWATERSHED)
The smallest drainage unit of a watershed for which stormwater management criteria have been established in the stormwater management plan.
SUBDIVISION
The division or redivision of a lot, tract, or parcel of land by any means into two or more lots, tracts, parcels or other divisions of land including changes in existing lot lines for the purpose, whether immediate or future, of lease, partition by the court for distribution to heirs, or devisees, transfer of ownership or building or lot development; provided, however, that the subdivision by lease of land for agricultural purposes into parcels of more than 10 acres, not involving any new street or easement of access or any residential dwelling shall be exempted.
SWALE
A low-lying stretch of land which gathers or carries surface water runoff.
TIMBER OPERATIONS
Refer to "forest management."
TIME OF CONCENTRATION (Tc)
The time for surface runoff to travel from the hydraulically most distant point of the watershed to a point of interest within the watershed. This time is the combined total of overland flow time and flow time in pipes or channels, if any.
TOP OF BANK
Highest point of elevation in a stream channel cross section at which a rising water level just begins to flow out of the channel and over the floodplain,
TOWNSHIP
Worcester Township, Montgomery County, Pennsylvania.
TOWNSHIP ENGINEER
A professional engineer licensed as such in the Commonwealth of Pennsylvania and appointed by Worcester Township pursuant to the Pennsylvania Second Class Township Code.[6]
TRIBUTARY AREA
The portion of a watershed that contributes runoff to a particular point in that watershed.
VERNAL POOL
Seasonal depressional wetlands that are covered by shallow water for variable periods from winter to spring, but may be completely dry for most of the summer and fall.
VOLUMETRIC RUNOFF COEFFICIENT
A variable indicative of stormwater runoff volume and dependent on the impervious coverage for a site.
WATER QUALITY VOLUME
A calculated volume of stormwater runoff from impervious areas which is required to be captured and treated at a site and may be achieved through use of structural or nonstructural BMPs.
WATERCOURSE
An intermittent or perennial stream of water, river, brook, creek, or swale identified on USGS or SCS mapping; and/or delineated waters of the commonwealth.
WATERS OF THE COMMONWEALTH
Any and all rivers, streams, creeks, rivulets, ditches, watercourses, storm sewers, lakes, dammed water, wetlands, ponds, springs, and all other bodies or channels of conveyance of surface and underground water, or parts thereof, whether natural or artificial, within or on the boundaries of this commonwealth.
WATERS OF THE UNITED STATES or WATERS OF THE US
(1) 
All waters which are currently used, were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters which are subject to the ebb and flow of the tide;
(2) 
All interstate waters, including interstate "wetlands";
(3) 
All other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds the use, degradation, or destruction of which would affect or could affect interstate or foreign commerce including any such waters:
(a) 
Which are or could be used by interstate or foreign travelers for recreational or other purposes;
(b) 
From which fish or shellfish are or could be taken and sold in interstate or foreign commerce; or
(c) 
Which are used or could be used for industrial purposes by industries in interstate commerce;
(4) 
All impoundments of waters otherwise defined as waters of the United States under this definition;
(5) 
Tributaries of waters identified in Subsections (1) through (4) of this definition;
(6) 
The territorial sea; and
(7) 
Wetlands adjacent to waters (other than waters that are themselves wetlands) identified in Subsections (1) through (6) of this definition.
WET BASIN
Pond for runoff management that is designed to detain runoff and always contains water.
WETLAND
Those areas that are inundated or saturated by surface- or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions, including swamps, marshes, bogs, ferns, and similar areas.
WETLAND DELINEATION
The process by which wetland limits are determined. Wetlands must be delineated by a qualified specialist according to the 1989 Federal Manuals (as amended) for the Delineation of Jurisdictional Wetlands (whichever is greater) or according to any subsequent federal or state regulation. Qualified specialist shall include those persons being Certified Professional Soil Scientists as registered with Registry of Certified Professionals in Agronomy Crops and Soils (ARCPACS); or as contained on consultant's list of Pennsylvania Association of Professional Soil Scientists (PAPSS); or as registered with National Society of Consulting Soil Scientists (NSCSS), or as certified by state and/or federal certification programs; or by a qualified biologist/ecologist.
[1]
Editor's Note: See 33 U.S.C. § 1251 et seq.
[2]
Editor's Note: Chapter 92 of Title 25 of the Pennsylvania Code was reserved 10-8-2010, effective 10-9-2010. It was replaced by Chapter 92a, National Pollutant Discharge Elimination System (NPDES) Permitting, Monitoring and Compliance.
[3]
Editor's Note: Chapter 92 of Title 25 of the Pennsylvania Code was reserved 10-8-2010, effective 10-9-2010. It was replaced by Chapter 92a, National Pollutant Discharge Elimination System (NPDES) Permitting, Monitoring and Compliance.
[4]
Editor's Note: See 35 P.S. § 691.1 et seq.
[5]
Editor's Note: See 32 P.S. § 680.1 et seq.
[6]
Editor's Note: See 53 P.S. § 65101 et seq.